In elevator installations having an elevator car connected with a counterweight by way of support means the counterweight moves in opposite direction to the elevator car. The elevator car and the counterweight are in that case respectively guided in their own substantially rectilinear guide tracks. A pressure shock in the elevator shaft, which can cause vibrations and noise, can occur when the counterweight passes the elevator car particularly in single elevator shafts and with fast-moving elevator cars. Moreover, the sudden pressure change, which is connected therewith, in the elevator car can be unpleasant for the passengers or the vibrations can be sensed as disturbing. The elevator installation then has deficient travel comfort. Disruptive noises can also arise in buildings in which the elevator installation is located.
These problems occur particularly with present-day elevator installations, since there is increasing effort to reduce the enclosed space as much as possible and to accommodate components of the elevator installation in the smallest possible space.
This problem of crossing of the counterweight and the elevator car in the elevator shaft has been known for a long time. However, previously only one solution of interest to deal with disadvantages arising during crossing of two elevator cars was offered. This solution is of recent date and is evident from the Japanese patent application of the company Toshiba Corp., with the publication number 2002003090 A. This patent application is concerned with elevator installations in multiple elevator shafts with several elevator cars which move past one another. It is proposed to reduce the speed of the cars, before meeting in the elevator shaft, by means of a control so as to prevent creation of noises and vibrations. Passengers can, however, perceive this reduction in speed as unpleasant. In addition, the conveying capacity of the overall installation is reduced, because a longer travel time results due to the reduction in speed.
In addition, there are numerous solutions concerned with improvement of aerodynamics, i.e. the air resistance, of elevator cars, but intrinsically say nothing about the problem of pressure shock and possible solutions.